基于热致液晶弹性体的仿生心脏泵的设计

为设计一款仿生心脏功能较佳的心室泵,采用柔性、热致伸缩的热致形变弹性体代替心肌,根据螺旋心室心肌带理论,选择心肌带的左心室段,并选取了Hilbert平面填充曲线作为热致导体在热致形变弹性体中的走行方式,设计出与真实心脏类似的心室泵结构.通过试验测量了所设计的心室泵的射血分数与心率,结果显示该心室泵的搏出量高于自然心脏,而其心率远低于自然心脏.相对于机械泵,所设计的心室泵结构与真实心脏类似,具有收缩能力强,射血分数高的优点,且不易破坏血细胞,生物相容性较好.不足之处在于,热致动液晶弹性体变形响应慢,暂时还未能达到正常心脏的心率.论证了构建双稳态结构,提高仿生心室泵效率的可能性,以及对于心肌纤维走向较为复杂的其他心肌带段,双轴拉伸机械雕刻对其仿生的可能性.此研究可为容积心脏泵的研发提供新的思路,也可以对右心衰竭等心脏疾病起到辅助治疗的作用.

Design of biomimetic heart pump based on thermo-actuated liquid crystal elastomer

In order to design a ventricular pump with better bionic heart function,the myocardium is replaced by thermo-deformable elastomer which is of flexibility and thermostriction. And a bionic heart ventricle pump is designed, according to the spiral ventricular myocardial band theory, the left ventricular segment of the myocardial band and the Hilbert plane filling curve are used. The experiment is designed to measure the ejection fraction and heart rate of the ventricular pump, and the results show that the stroke volume of the ventricular pump is higher than the natural heart, and its heart rate is much lower than the natural heart. Compared with the mechanical pump, the structure of the ventricular pump designed is more similar to the real heart, with stronger contraction ability, higher ejection fraction, and better biocompatibility. The disadvantage is that the thermally actuated liquid crystal elastomer responses to the deformation slowly and has not yet reached the normal heart rate. The possibility of constructing a bistable structure to improve the efficiency of the biomimetic ventricular pump is discussed. For other myocardial band segments with more complicated myocardial fiber orientation, the possibility of biaxial stretching mecha-nical engraving is discussed. This research can provide new ideas for the research and development of volumetric heart pumps, and also play a role in adjuvant therapy for heart diseases such as right heart failure.